Correlation Between Aortic Valve Area Measured by Cardiac Computed Tomography and Transthoracic Echocardiography in Patients with Aortic Stenosis

Background: Accurate assessment of aortic valve area (AVA) is essential for determining the severity of aortic stenosis (AS) and guiding clinical management. Transthoracic echocardiography (TTE) is the standard first-line imaging modality, while cardiac computed tomography (CT) provides direct anatomical planimetry and may offer complementary information in selected patients. Objective: To evaluate the correlation and agreement between CT-derived and TTE-derived AVA measurements and to examine their association with clinical outcomes in patients with AS. Methods: This single-center retrospective cohort study included 1,857 consecutive adults with moderate to severe AS who underwent both TTE and cardiac CT at the Rawalpindi Institute of Cardiology between January 2023 and July 2025. Correlation between modalities was assessed using Pearson’s coefficient, while agreement was evaluated with Bland–Altman analysis. Associations between AVA thresholds (≤1.0 cm² vs >1.0 cm²) and adverse clinical outcomes were analyzed using logistic regression and receiver operating characteristic (ROC) analysis. Results: The mean AVA measured by TTE was 0.84 ± 0.19cm² and by CT was 0.87 ± 0.21 cm². A strong correlation was observed between the two modalities (r = 0.82, p < 0.001), with acceptable agreement on Bland–Altman analysis. Patients with AVA ≤ 1.0 cm² had significantly higher rates of adverse clinical outcomes compared with those with larger valve areas. Conclusion: CT-derived AVA demonstrates strong agreement with TTE and provides complementary information for severity assessment and risk stratification in patients with aortic stenosis. Integrating CT with conventional echocardiography may improve clinical evaluation, particularly in cases with discordant or borderline findings.